Search found 10 matches

by jak
Wed Jan 12, 2022 6:38 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: XPBD rigid-body simulation with hard penetration constraints
Replies: 4
Views: 567

Re: XPBD rigid-body simulation with hard penetration constraints

Nice demo. Always nice to be able to just click a link and see something running in the browser. I reckon you'll figure it out if you just keep at it. Again, bugs like this could be a million different things, so it would be hard to diagnose remotely. But because apparently I like making random unif...
by jak
Wed Dec 29, 2021 1:50 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Small Step XPBD FEM Demo
Replies: 6
Views: 3066

Re: Small Step XPBD FEM Demo

Updated the demo. The current version is still at https://jak-xyz.github.io/xpbd-fem, and the previous version is now at https://jak-xyz.github.io/xpbd-fem/v4. This update is a bit different in nature compared to the previous ones, as I added very few features to the main sim. Instead, I added two n...
by jak
Tue Dec 07, 2021 10:30 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: XPBD rigid-body simulation with hard penetration constraints
Replies: 4
Views: 567

Re: XPBD rigid-body simulation with hard penetration constraints

Hard to say from just the video, so this probably won't be accurate, but maybe it'll still help in a rubber-ducking kind of way. The first thing it makes me think is that somewhere in your velocity/restitution code you're using full Δt instead of the substep Δt. You could try turning off restitution...
by jak
Mon Nov 08, 2021 12:03 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Small Step XPBD FEM Demo
Replies: 6
Views: 3066

Re: Small Step XPBD FEM Demo

Love it! That GPU sim is so smooth ~~

Great to see other people working in the area!
by jak
Sat Nov 06, 2021 6:31 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Small Step XPBD FEM Demo
Replies: 6
Views: 3066

Re: Small Step XPBD FEM Demo

Updated the demo. The current version is still at https://jak-xyz.github.io/xpbd-fem, and the previous version is now at https://jak-xyz.github.io/xpbd-fem/v3. Additionally, I uploaded the latest code to: https://github.com/jak-xyz/xpbd-fem. Changelog: Rayleigh Damping Took a deeper dive into the Ra...
by jak
Fri Oct 08, 2021 11:15 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Small Step XPBD FEM Demo
Replies: 6
Views: 3066

Re: Small Step XPBD FEM Demo

The excellent paper Miles Macklin posted yesterday ( A Constraint-based Formulation of Stable Neo-Hookean Materials ) elucidated some things about the relationship between constraints and energy in XPBD that I had been fuzzy on, and I couldn't resist jamming the corrected mixed Neo-Hookean energy fu...
by jak
Thu Oct 07, 2021 4:58 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Small Step XPBD FEM Demo
Replies: 6
Views: 3066

Re: Small Step XPBD FEM Demo

Found a sudden burst of inspiration to post an update to the demo ;p. The 3 major additions are a few new element types (second-order triangles and first- and second-order tetrahedrons), Stanford armadillo meshes for each of the element types, and a new set of energy functions that constrain per-ver...
by jak
Sun Aug 29, 2021 6:00 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Small Step XPBD FEM Demo
Replies: 6
Views: 3066

Small Step XPBD FEM Demo

Hi guys, I've been working on a small step XPBD-based implementation of FEM off and on for the last several months, and I think I finally have something that someone might find interesting. Here's a WASM demo showing the current state of things: https://jak-xyz.github.io/xpbd-fem/. At some point I h...
by jak
Fri Jul 09, 2021 11:52 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Damping in XPBD
Replies: 3
Views: 4607

Re: Damping in XPBD

Your code certainly looks correct on first glance, though I didn't try to run it, so who knows. I would expect it has more to do with getting everything else set up perfectly to make Rayleigh damping "happy". I was thinking of doing a post on what I've got so far in a little bit, and I was...
by jak
Tue Jul 06, 2021 11:37 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Damping in XPBD
Replies: 3
Views: 4607

Re: Damping in XPBD

I realize this question is over a year old (so I hope OP was able to figure something out!), but it still comes up on google and it got me doubting the suggested Rayleigh damping from the XPBD paper for use with incompressible FEM. However, after quite a few pitfalls along the way, I finally got it ...